Methods of electrophysiological testing

Abstract

In electrophysiology, methods of testing a subject's neural mechanisms of learning and memory in order to quantitatively diagnose the subject's brain dysfunction require specified conditions or stimuli to evoke his electrical brain activity, which are his response or non-response to the stimuli. These evoked responses are quantitatively interpreted by challenges which specify analytic protocol. A test using letter reversal conditions identifies a subject's problems relating to pattern reversal and perception. A test involving figure-ground condition in which a primary stimulus is obscured with secondary stimuli indicates a subject's ipsimodal and cross-modal inhibition. A test using a standard-interruptive condition, in which a series of standard and interruptive stimuli are alternated, indicates a subject's conditionability, sensitization and recovery cycle.

What is claimed is: 
     
       1. A method of testing subjects to characterize the subject's ability to inhibit sensory stimulation which comprises: (a) attaching electrodes to the subject's head and presenting the subject with primary meaningful sensory stimulus,   (b) simultaneously superimposing secondary meaningless sensory stimuli on said primary sensory stimulus,   (c) sensing the electrical brain responses of the subject,   (d) presenting the subject with said secondary stimuli without said primary stimulus,   (e) sensing the subject's electrical brain responses,   (f) making a first comparison using a digital computer-based system of the responses evoked by said primary and secondary stimuli with the responses evoked by said secondary stimuli alone, and   (g) making a second comparison using a digital computer-based system of said first comparison with a set of standard norms as an indication of the subject's ability to inhibit secondary stimuli.   
     
     
       2. A method as in claim 1 wherein the primary stimulus is a visual display and the secondary stimuli are auditory, visual and somatosensory. 
     
     
       3. A method as in claim 1 wherein said primary stimulus is an audio recording and said secondary stimuli are auditory, visual and somatosensory. 
     
     
       4. A method of testing subjects to identify pattern perception and reversal problems which comprises: (a) attaching electrodes to the subject's head and presenting to the subject a visual display in sequence of a series of known, individually identifiable patterns comprising the pairs of letters and numbers selected from the set comprising "p", "q" and "d", "b" and "6", "9" and "M", "W" which have specific meanings in a specific orientation;   (b) sensing the subject's electrical brain response;   (c) making a first comparison using a digital computer-based system of the subject's responses to a first set of known identifiable patterns at specific orientations, for example, "d", "b", with a second and associated set of such patterns, for example, "d", "d", and   (d) making a second comparison using a digital computer-based system of said first comparison with a set of standard norms to characterize the subject's pattern reversal, recognition and perceptual powers.   
     
     
       5. A method of testing subjects to identify conditionability and sensitization which comprises: (a) subjecting the subject to specified alternating series of standard and interruptive stimuli, said standard stimuli comprising a first series of regularly repeated selected stimuli and said interruptive stimuli, a second series of regularly repeated stimuli which differs from said first series and has two different stimuli in each member of the series;   (b) sensing the subject's electrical brain responses;   (c) making a first comparison using a digital computer-based system to determine the subject's responses to said interruptive stimuli on the response to said standard stimuli; and   (d) making a second comparison using a digital computer-based system to determine the deviation of the first comparison from a set of standard norms.   
     
     
       6. A method as in claim 5 wherein said standard series of stimuli comprises a flash, click and tap each separated by 1 sec. and repeated 50 times to produce 150 individual stimuli. 
     
     
       7. A method as in claim 5 wherein the first interruptive stimuli series comprises 200 paired flash-click combinations where said flash is followed by a click 250 msec. later. 
     
     
       8. A method as in claim 5 wherein the second interruptive stimuli series comprises 200 paired click-flash combinations where said click is followed by a flash 250 msec later. 
     
     
       9. A method of interrogating subjects to characterize the recovery cycle which comprises: exposing the subject to a specified alternating series of standard and interruptive stimuli,   sensing the electrical brain responses, and   comparing the response to the unconditioned stimulus to the response to the standard stimulus,   wherein said standard series of stimuli comprises a flash, click and tap each separated by 1 sec and repeated 50 times to produce 150 individual stimuli.   
     
     
       10. A method as in claim 9 wherein a first interruptive stimuli series comprises 200 paired flash-click combinations where said flash is followed by a click 250 msec later. 
     
     
       11. A method as in claim 9 wherein a second interruptive stimuli series comprises 200 paired click-flash combinations where said click is followed by a flash 250 msec later.